#include <iostream>
using namespace std;


void main()
{
	const int n=10;
	int mas [n]={1,2,3,4,5,6,7,8,9,10};
	int *pa=mas;
	int buf;
	for(;*pa<n;pa+=2)
	{
		buf=*pa;
		*pa=*(pa+1);
		*(pa+1)=buf;
		
	}
	for(int i=0;i<n;i++)
	{
		cout<<mas[i];
	}

	cout<<endl;

}